说明：  propose a new routing technique called Security-Aware ad hoc Routing (SAR) that incorporates security attributes as parameters into ad hoc route discovery. SAR enables the use of security as a negotiable metric to improve the relevance of the routes discovered by ad hoc routing protocols. We develop a two-tier classification of routing protocol security metrics, and propose a framework to measure and enforce security attributes on ad hoc routing paths. Our framework enables applications to adapt their behavior according to the level of protection available on communicating nodes in an ad hoc network.